Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add synthesisengineering/synthesis-skills --skill synthesis-fact-checkinggit clone --depth 1 https://github.com/synthesisengineering/synthesis-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/synthesisengineering/synthesis-skills/synthesis-fact-checking)<a href="https://agentmods.dev/skills/synthesisengineering/synthesis-skills/synthesis-fact-checking"><img src="https://agentmods.dev/badge/skills/synthesisengineering/synthesis-skills/synthesis-fact-checking/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/synthesisengineering/synthesis-skills/synthesis-fact-checking"><img src="https://agentmods.dev/badge/skills/synthesisengineering/synthesis-skills/synthesis-fact-checking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Excessive Agency · line 455 Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00117 | $0.07566 |
| Opus 5 | $0.00059 | $0.03783 |
| Sonnet 5 | $0.00023 | $0.01513 |
| Haiku 4.5 | $0.00012 | $0.00757 |
Grade A, and why
synthesis-fact-checking scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 508 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fact-Check Process for Articles and AI-Synthesized Content
Purpose
This skill provides a repeatable process for verifying factual accuracy of articles, blog posts, and news content before publication. v2.0 is specifically calibrated for the recursive-contamination problem: AI-generated text now constitutes a plurality of newly indexed English-language web pages (per Ahrefs measurement of newly indexed pages in April 2025), which means AI outputs become source material for the next generation of AI outputs and human research. Multi-source confidence requires graph independence, not raw count.
The companion skill, synthesis-content-quality, addresses stylistic and substantive quality. This skill addresses factual correctness.
What v2.0 adds
- Nine new protocol sections (C1) for the structural gaps in v1.1.0: nested attribution, paraphrase boundary drift, composite quotes, position-shifting, source-translation drift, URL rot vs hallucination, AI-generated synthetic sources, citation laundering chains, tool-specific hallucination patterns. Full detail in references/detailed-protocols.md.
- Per-family hallucination signatures. Claude over-produces plausible-seeming DOIs; GPT invents URLs on real domains; Gemini drifts to vague "studies show"; DeepSeek language-mixes under reasoning; Llama fabricates above approximately 32K context per RIKER benchmark; Grok fabricates X/Twitter quotes. Family-conditional detection is the bucket-C parallel to bucket-A's family-conditional stylistic detection. Full detail in references/per-family-hallucination-signatures.md.
- Graph-independence revision to section 2 (Multi-Source Confidence Framework). Citation laundering chains collapse cross-source corroboration to a single AI-generated upstream. Confidence conditions on graph independence, not on raw count. Full detail in references/citation-laundering-detection.md.
- Section 4 refresh. Updated examples from 2025-2026 production incidents: Mostafavi sanction ($10,000), Goldberg Segalla sanction ($59,500 total), Chicago Sun-Times summer reading list, Springer "Mastering ML" book retraction, BBC/EBU 45 percent significant-issues rate, Topaz et al. May 2026 Lancet letter (1 in 277 PubMed papers referencing fabricated paper, twelvefold rise from 2023), Damien Charlotin's database of 1,455+ sanctioned legal cases, Mata v. Avianca, Stanford RegLab Magesh measurement (17 to 33 percent legal-AI hallucination rate). Full incident archive in references/production-incident-archive.md.
- Section 4f demote. Hallucinated citations as a single bucket is demoted. The failure mode splits into the C1-URLROT-001 / C1-SYNTH-001 / C1-LAUNDER-001 trio plus residual pure-fabrication.
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 508 lines · 117 tokens per session scan A 2003b3aff293
synthesis-fact-checking is a skill published in the GitHub repository synthesisengineering/synthesis-skills (18 stars, last pushed 2d ago), licensed Apache-2.0. It adds 117 tokens to every session and 7,566 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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